Habitat characteristics, temporal variability, and macroinvertebrate communities associated with a mat-forming nuisance diatom (Didymosphenia geminata) in Catskill mountain streams, New York

• Published in: Aquatic sciences 2014-10, Vol.76 (4), p.553-564
• Main Authors: Richardson, David C, Oleksy, Isabella A, Hoellein, Timothy J, Arscott, David B, Gibson, Catherine A, Root, Samantha M
• Format: Article
• Language: English
• Subjects: Algae; Animal and plant ecology; Animal, plant and microbial ecology; Applied ecology; Aquatic ecosystems; aquatic food webs; Bacillariophyceae; Biological and medical sciences; Biomedical and Life Sciences; Conservation, protection and management of environment and wildlife; correlation; Didymosphenia geminata; Ecology; floods; Food webs; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Habitats; Invasive species; Invertebrates; Life Sciences; Macroinvertebrates; Marine & Freshwater Sciences; Mountains; nitrates; Nonnative species; Nuisance; Oceanography; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Plant cytology, morphology, systematics, chorology and evolution; Regulated rivers; Research Article; River regulations; rivers; Shear stress; storms; Streams; summer; Synecology; temporal variation; Thallophyta
• ISSN: 1015-1621; 1420-9055
• DOI: 10.1007/s00027-014-0354-7

Didymosphenia geminata has recently and rapidly greatly expanded its range and abundance, sometimes as an exotic invasive and other times as a nuisance (‘native invader’) within its hypothesized native range, including the northeastern United States. D. geminata mats are visually conspicuous and can grow >10 cm thick. Mats first appeared in the eastern Catskill mountains (New York) in 2009. Our objectives were to (1) document D. geminata growth in three impounded or regulated rivers in the eastern Catskill mountains from 2010 to 2012 and (2) measure the effects of D. geminata mats on macroinvertebrates. The highest D. geminata cell densities were downstream of reservoir outflows in two of three streams. D. geminata mat development peaked in the summer each year, but maximum coverage and cell density was variable among years. D. geminata cover was negatively correlated with 10 days maximum antecedent shear stress, and the year with lowest mean D. geminata cover had multiple tropical storms and floods, suggesting that low variation in flow allows for D. geminata mat proliferation. Across sites, D. geminata density was negatively correlated with nitrate concentrations. D. geminata density was negatively related to macroinvertebrate richness suggesting that D. geminata mats may negatively affect aquatic food webs. D. geminata appears to be a nuisance species with similar habitat characteristics and growth where it is both a native invader and an invasive species.